Red rice porridge - Unzou porridge

…Today, potato porridge usually refers to a dish containing sweet potatoes, but the Heian period dish depicted in Akutagawa Ryunosuke's "Imogayu" (Potato Porridge) was also called shiyoyogayu (sweet potato porridge), a kind of sweet soup made by simply cutting up yams and boiling them in sweet arrowroot juice. Porridge is often eaten on special occasions, and in addition to the seven-herb porridge and red bean porridge for New Year's Day, obanagayu (flower porridge) was eaten at the Imperial Court on August 1st, and red lees porridge (red lees porridge) was eaten at temples on December 8th. Obanagayu is said to have originated in the ancient rituals at Misayama, Suwa Taisha Shrine, where Japanese silver grass was burned black and mixed into the porridge, but later black sesame seeds came to be used instead. …

*Some of the terminology explanations that refer to "red porridge" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…芋粥は，現在ではふつうサツマイモを入れたものを指すが，芥川竜之介の《芋粥》に描かれた平安時代のそれは薯蕷（しよよ）粥ともいい，ヤマノイモを切って甘葛（あまずら）の汁で煮ただけの，汁粉のようなものであった。粥はハレの日の食物とされることが多く，正月の七草粥，小豆（あずき）粥のほか，8月1日には宮中などで尾花粥，12月8日には寺院などでは紅糟（うんぞう）粥を食べた。尾花粥は古く諏訪大社の御射山（みさやま）の神事に始まるといい，ススキを黒焼きにして粥に混ぜたものだったが，後には黒ゴマを代用するようにもなった。…

※「紅糟粥」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報